>>3906298Overall, I'd say that agents definitely look for artists who are already established.
However, you can still get lucky and get signed on to an agency very early on - often times straight out of art school. I follow a lot of illustrators who have agents, and even reached out to some for agent advice. From what I gather, the ways people have landed their agents are:
1. The illustrator reached out to the agent to share their portfolio
2. The agent saw their work out in the world and offered to sign them
3. The illustrator was referred to the agent by another illustrator who was already signed
4. The agent tried to discover new talent and found them as they were graduating art school.
5. The illustrator previously had an agent but for whatever reason they want to work with a new one
Cold calling art agencies is technically a viable way of 'breaking in' to higher-tier work. However, it's not going to be easy at all. A lot of agencies often have some sort of instructions on how to submit portfolios for consideration.
I don't know if this is obvious or, but if you want to be doing any of this (cold calling art directors, agencies, etc.) then you need to get your own standalone portfolio site - something more professional than a social media blog, and something that is curated with your best, most relevant work. It's supposed to act as a snapshot of your best work, so that if someone looks at it for 5 seconds, they already know exactly what it is that you do. I personally use Squarespace (I liked their free themes the best), but Wix and Weebly are good. I wouldn't recommend coding your own custom site unless you're very good at that stuff.